Carbon canister for vapor recovery systems

ABSTRACT

A carbon canister as utilized relative to underground fuel storage tank vapor recovery, including for the capture and purging of hydrocarbon vapors as air is introduced into and released from an underground storage tank, and wherein, in one form intended primarily for use in Stage II Vapor Recovery systems, the carbon canister includes a valve activated by weight of saturated carbon and wherein, in another form intended primarily for use in Stage I Vapor Recovery systems, the carbon canister is a free breathing carbon canister with a surge protection device.

CROSS REFERENCE TO RELATED APPLICATIONS

This continuation-in-part application claims priority to thenon-provisional application having Ser. No. 12/322,414, filed Feb. 2,2009, now U.S. Pat. No. 8,0756,677 which is a continuation-in-part ofthe non-provisional application having Ser. No. 11/500,211 which wasfiled on Aug. 7, 2006, now U.S. Pat. No. 7,578,872 and which claimspriority to the provisional patent application having Ser. No.60/797,599, which was filed on May 4, 2006.

Also, this non-provisional patent application is related to thenon-provisional patent application having Ser. No. 11/043,526, which wasfiled on Jan. 26, 2005 (now U.S. Pat. No. 7,011,119), which claimspriority to the provisional application having Ser. No. 60/539,848,which was filed on Jan. 28, 2004.

FIELD OF THE INVENTION

The present invention is directed to a vapor recovery system, ingeneral, and more specifically to a carbon canister as utilized relativeto underground fuel storage tank vapor recovery, including for thecapture and purging of hydrocarbon vapors as released from anunderground storage tank both when fuel is delivered to the undergroundstorage tank and when a vehicle is being fueled from the undergroundstorage tank.

One form of the invention is directed to a carbon canister with a valveactivated by weight of saturated carbon and intended primarily for usein Stage II Vapor Recovery systems that are employed to capture gasolinevapors, including such as when a vehicle is being fueled from theunderground tank.

Another form of the invention is directed to a free breathing carboncanister with a surge protection device and intended primarily for usein Stage I Vapor Recovery systems that are employed to capture gasolinevapors, including such as when gasoline is delivered to the storagetank.

A unique aspect of at least one form of the present invention istransfer of underground storage tank pressure control from the carboncanister to a pressure vacuum valve at a pressure reading ofapproximately at least 0.25 inches of water.

Another unique aspect of at least one form of the present invention isthe capability of testing and verifying operability of the weightactivated valve included in the carbon canister.

BACKGROUND OF THE INVENTION

The subject carbon canisters of the present invention relate to thecapture and purging of hydrocarbon vapors as air is drawn into anunderground storage tank and released therefrom, such as during fuelingby ORVR vehicles and when fuel is delivered to the underground storagetank.

Fuel storage tanks, such as underground storage tanks, UST, used tostore fuel at gasoline dispensing facilities or GDF, are subject tovariable pressures that affect the ability of the fueling system andvapor recovery system to operate correctly. The fuel storage tanks thushave one or more vents which release the excess pressure when the tankexceeds a predetermined maximum pressure. Excess pressure can be causedby vacuum assisted refueling when more vapors are drawn into the tankthan volume of fuel dispensed, by not connecting the vapor return hoseto the transfer tank when refueling the tank, or by local atmosphericconditions, particularly barometric pressure changes associated withweather. Additionally, negative pressure, or partial vacuums, can appearin the storage tank by dispensing more fuel than vapors that are drawninto the tank as during vacuum assist, or balance system, refueling. Inthat situation, the tank requires additional pressure, or, more likely,the vacuum must be dissipated.

Since the 1998 automotive model year, onboard refueling vapor recovery,ORVR, technology has been employed, initially on passenger cars andpresently on light trucks. As is well known, the motorist refuels avehicle at a service station. The fuel is pumped from an undergroundtank, by the dispenser, through a hose and nozzle, for filling thevehicle fuel tank. Normally, the vapors generated within the fuel tank,through refueling, are returned through the vapor path of the fuel hose,back to the dispenser, either by the balanced pressure method—calledStage II vapor recovery—or by a pump, and then are returned to theunderground storage tank for containment.

Escaped gasoline vapors raise pollution concerns and triggergovernmental regulations. Hydrocarbon vapors, such as octane, under theaction of sunlight form ground level ozone. Such ozone affects therespiratory tract in humans. Normally, balance type Stage II vaporrecovery stations operate at a negative pressure except during closureof the station. When an ORVR equipped vehicle is refueled, the ORVRsystem retains the vapors from the vehicle fuel tank, and does notreturn the vapors to the dispensing system, often lowering the pressurewithin the fuel storage tank. An ORVR vehicle refueling at a Stage IIequipped station imposes a negative pressure on the Stage II system thatdraws some atmospheric air into an underground fuel tank. Theatmospheric air then absorbs hydrocarbon vapors released from storedfuel, and with each ORVR vehicle that refuels the pressure in theunderground tank decreases. When that pressure exceeds a limit, valvesrelease the air containing hydrocarbons from the tank to the atmosphere,thus contributing to pollution when attempting to avoid it.

Generally, various methods are employed to capture gasoline vapors andthen return them to the underground tank. The vapor recovery systems, indoing so, prevent vapors from escaping to the atmosphere as componentsof pollution. Vapor recovery systems are of two types. First, the vacuumassist system utilizes the partial vacuum created within the nozzle, bymeans of the flowing fuel passing through the nozzle during itsdispensing, or a vacuum pump, and this partial vacuum tends to attractvapors back into the nozzle, either through a bellows arrangement usedin conjunction with the nozzle spout, or through a passage createdbetween concentrically arranged nozzle spouts, that allows the partialvacuum to attract the vapors back into the spout for return to theunderground storage tank. Second, the balanced pressure system beginsupon pumping gasoline into an automobile fuel tank, and then displacedvapors are forced back towards the emplaced nozzle that capturesgasoline vapors for return back into the vapor line and eventually tothe underground storage tank.

Prior art designs defeat pressurization and vapor absorption in theunderground fuel tank by two classes of devices. First, nozzles andother parts of the dispensing system are regulated by an ORVR detectingsensor. The sensor recognizes the pressure dip caused by an ORVR vehicleand promptly reduces air ingestion to less than the volume of fueldispensed. The sensor and nozzles result in a slight negative pressurein the underground tank that limits vapor loss to the atmosphere.Second, membranes and condensing processes control the vapor at thesource, in the underground fuel tank. The membranes and condensingprocesses cool or otherwise liquefy gasoline vapors and return them tothe underground tank while letting cleansed air return to theatmosphere. Though collecting vapors, the prior art required additionalmechanical equipment, and has higher installation and operational costs,and; energy consumption.

The patent to Healy, U.S. Pat. No. 5,305,807, describes a vapor recoverydevice. This device has a vacuum pump connected to underground storagetanks coupled with a solenoid. A pressure switch monitors pressure inthe UST and energizes the solenoid to move valves within threeconditions to direct air flow into or out of the UST. The valves controlflow of hydrocarbons and air through a conduit system. This patentdiscloses a pump and solenoid not in the present invention.

Additionally, the California Air Resources Board “CARB” has imposedEnhanced Vapor Recovery upon equipment used at gasoline dispensingfacilities. The Assignee has developed an activated carbon canister withan internal pressure control system for a UST. The internal pressurecontrol system goes by the name of a vapor processor according to CARB.In a typical UST, a pressure vacuum valve vents the pressure andhydrocarbon emissions from a UST when the pressure reading exceeds 2.5inches of water. However, some vapor processors can release hydrocarbonsat pressure exceeding 0.25 inches of water. The order of magnitudereduction in pressure has concerned CARB that more hydrocarbons will beemitted by vapor processors and that the pressure vacuum valves will bebypassed and no longer serve their function at suitable pressure levels.Additionally, CARB seeks the pressure vacuum valve to operate in theevent of a vapor processor failing. Existing vapor processors do notprovide a mechanism or method to transfer pressure control from thevapor processor back to the pressure vacuum valve.

The present art overcomes the limitations of the prior art. That is, atleast one form of the present invention, a canister of activated carbonwith a valve actuated by the weight of saturated carbon, provides amechanical closing of an inlet valve returning pressure control to thepressure vacuum valve. Such form of the present invention returnspressure control before or when it is saturated with hydrocarbon vaporsthus allowing the pressure vacuum valve to regulate hydrocarbon vaporsthat accumulate before or beyond saturation at less than 2.5 inches ofwater pressure.

Thus, prior art devices do not provide for storing purged hydrocarbonvapors within a container and preventing their return into anunderground fuel tank while allowing air to pass freely through thecontainer. At least one form of the present invention, hereinafter oftenreferred to as the Stage II form of the invention, uses the heavierweight of carbon saturated with hydrocarbons as an input to close avalve. Such form of the present invention does not require electricalpower or an external control to actuate.

The form of the invention more particularly directed to Stage I vaporrecovery, such as when the storage tank is being filled with fuel, suchas from a tank truck, unlike the Stage II form, does not require a valveactivated by weight of the saturated carbon to affect the capture andpurging of hydrocarbons. Like the Stage II form, such Stage I formemploys a carbon canister, but the canister is designed to be freebreathing and includes a surge protection device to prevent high flowrates through the canister in case an improper fuel delivery is made,but no weight activated valve. Such form can therefore be viewed in manyregards as a simplified or stripped down form of the Stage II form, buta form that nevertheless operates effectively in Stage I recoverysystems to efficiently capture and purge hydrocarbons from the airpassing through the canister as fueling operations occur. Such Stage Iform is particularly appropriate for use at service stations withoutStage II vapor recovery.

SUMMARY OF THE INVENTION

The present invention employs, including in both its Stage II and StageI forms, a carbon canister that connects and communicates with pipingfrom an underground tank and through which air and vapors are passedbetween the atmosphere and the underground tank. Such invention thusincludes a canister, a containment area, such as a casing, inside thecanister, carbon within the containment, preferably activated carbon,and various valves and piping in communication with the atmosphere andthe underground tank. In the Stage II form of the invention, the carboncanister also includes a valve activated by the weight of saturatedcarbon contained therein whereas, in the Stage I form of the invention,the canister instead, more simply, is free breathing and includes asurge protection device, such as a flow limiting valve, or a surgevalve.

With particular reference to the form of the invention intendedprimarily for use in Stage II vapor recovery, when an ORVR vehiclerefuels, the pressure lowers in an underground tank that draws airthrough the valves into the canister. After refueling an ORVR vehicle,the underground tank remains subject to environmental conditions thatgenerate hydrocarbon vapors, such as octane C8H18. Barometric pressuredrops and evaporated fuel during long refueling lulls producehydrocarbon vapors at an increased pressure. Those hydrocarbon richvapors then return to the canister where the activated carbon binds thehydrocarbons while releasing air to the atmosphere. The activatedcarbon, now heavier with hydrocarbons, sinks lower in the canister andcloses a valve. Closing the valve keeps the remaining hydrocarbon vaporsin the UST. The refueling of more ORVR vehicles draws in atmospheric airthrough a bypass to purge the hydrocarbons retained in the canister andthus lighten the carbon. Once the activated carbon lightens enough inweight, the valve opens and hydrocarbon vapors return to the canisterfor adsorption. Unlike absorption where the hydrocarbon molecules bondto the carbon atoms, adsorption utilized in the present inventionprovides carbon upon which hydrocarbon molecules temporarily adherewithout bonding to the carbon atoms. This cycle of hydrocarbon vaporbinding and purging, regenerative carbon adsorption, continues with eachORVR vehicle.

With particular reference to the form of the invention intendedprimarily for use in Stage I vapor recovery; the carbon canister isinstead utilized in such a way to be repeatedly purged by the action ofthe fueling vehicles. The system is allowed to breathe freely in and outthrough the carbon canister so that the system is never at a positivepressure that would cause vapors to discharge to the atmosphere throughleaks in the system. The canister is equipped with a flow limiting valve(surge valve) that prevents high flow rates through the canister in casean improper fuel delivery is made. No valve activated by weight ofsaturated carbon or other means is necessary to keep the carbon canisterfunctioning to remove the hydrocarbons from the vapor.

The different forms of the invention thus share some common objects,but, in other regards, may have additional or separate objects fromthose of other forms.

It is a common object of the invention, including both the Stage II andStage I forms thereof, to provide a carbon canister that functions asair and vapors are directed and pass therethrough to reduce pollutionand improve air quality as fuel delivery thereto and fueling therefromoccurs.

It is also an object of at least one form of the invention to provide acarbon canister with weight actuated valve capable of removinghydrocarbons from vapors evacuated from an underground fuel tank.

It is another object of at least one form of the carbon canister withweight actuated valve to collect hydrocarbon laden vapors by pressureincreases within an underground fuel tank.

It is another object of at least one form of the carbon canister,including the form with a weight actuated valve, to collect atmosphericair into the canister by pressure decreases within an underground fueltank.

It is another object of at least one form of the carbon canister,including the form with a weight actuated valve, to purge collectedhydrocarbon vapors by passing atmospheric air through the canister as itis discharged back into the atmosphere.

It is another object of at least one form of the carbon canister,including the form with a weight actuated valve, to operate independentof electrical or mechanical power.

It is another object of at least one form of the carbon canister,including the form with a weight actuated valve, to permit readyinspection and changing of the activated carbon placed within thecanister.

It is another object of at least one form of the carbon canister,including the form with a weight actuated valve, to encourage prompt andaccurate manual and automatic adjustment in response to pressurefluctuations.

These and other objects may become more apparent to those skilled in theart upon review of the invention as described herein, and uponundertaking a study of the description of its preferred embodiment, whenviewed in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In referring to the drawings,

FIG. 1 illustrates a gasoline station where a vehicle refuels from anunderground tank connected to a vapor recovery system constructed inaccordance with the principles of the present invention;

FIG. 2 shows a detailed view of one form of the carbon canister andappurtenant valves and control mechanisms;

FIG. 3 describes a detailed view of the canister in an alternateembodiment of the present invention;

FIG. 4 shows a side view of one form of the canister of the presentinvention in communication with an underground storage tank;

FIG. 5 shows a sectional view of one form of the canister of the presentinvention intended particularly for use in Stage II vapor recoverysystems;

FIG. 5 a shows a sectional view of one form of the canister and flowlines during loading, FIG. 5 b shows a sectional view of the canisterand flow lines during secondary purging, and FIG. 5 c shows a sectionalview of the canister and flow lines during normal purging;

FIG. 6 shows a detailed sectional view of one form of the canister andthe weight actuated valve;

FIG. 7 provides a top view of one form of the canister of the presentinvention within the casing;

FIG. 8 shows a sectional view of the lower portion of an alternativecanister embodiment, the upper portion of which is similar in manyrespects to that of FIG. 5, wherein the canister of such alternativeembodiment includes apparatus permitting a technician to readily testoperations of the weight activated valve; and

FIG. 9 shows a sectional view, similar to FIG. 5, of another form of thepresent invention that is intended particularly for use in Stage I vaporrecovery systems.

The same reference numerals refer to the same parts throughout thevarious figures.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present art overcomes the prior art limitations by providing acarbon canister and appurtenant valves and controls to cleansehydrocarbon vapors from air released from an underground storage tankduring ORVR refueling. At service stations, ORVR equipped vehiclesrefuel, often inducing negative pressure upon an UST that draws inatmospheric air which blends with hydrocarbons in the UST. When the USTreaches a high enough pressure, relief valves open and vent thehydrocarbon laden air from the UST to the atmosphere.

In referring to FIG. 1, an embodiment of the canister 1 of the vaporpressure management system for vapor recovery, particularly intended foruse in a Stage II vapor recovery system, is shown connected to an UST 2in a refueling system 3. The UST has a vent stack 4 with an inletgenerally above the maximum fill line of the UST and here shown away andto the right of the canister of the invention. The vent stack thencommunicates to the canister 1 and retains an emergency pressure reliefvalve 4 a. A shutoff valve 4 b of the ball type is in the line from thevent stack to the canister. The line then connects to the canister.Opposite the line from the UST, the canister has a canister inlet 5. Theinlet has regulated communication with the atmosphere. The inletreceives atmospheric air under certain conditions or discharges air fromthe line under other conditions. The inlet may have threading forconnection to additional piping or a vent cap, not shown.

FIG. 2 shows one form of the present invention in more detail. Thecanister 1 has a generally cylindrical shape, here shown upright. Thecanister has a bottom 1 a and an opposite top 1 b. The bottom and thetop have openings to permit communication to the UST line 4 c and theinlet 5 respectively. Though a cylindrical shape is described,alternative shapes of the canister, rectangular, round, spherical, conicand the like, are anticipated. The canister has a wall 1 c that connectswith the perimeters of the top and the bottom to surround the canister.The canister contains activated carbon in dry form, generally fillingthe canister. The activated carbon has been specially processed toprovide increased levels of hydrocarbon adsorption per weight of carbon.Alternatively, the canister contains activated charcoal in an aqueoussolution.

The inlet 5 then proceeds to its first branch control 6. The firstbranch control communicates to the atmosphere for drawing in air throughthe canister to the UST. The first branch control has a vacuum regulator7 in communication with a valve 8 that connects with a screened intake9. The intake 9 admits atmospheric air into the canister generally at alow pressure and when the vacuum regulator 7 opens.

The inlet 5 has a second branch control 10. The second branch controlreleases treated air from the canister to the atmosphere. The secondbranch control has a pressure regulator 11 in communication with a valve12 that then connects with a screened exhaust or outlet 13. The outlet13 is hereby shown below the intake 9 however; other locations of themare anticipated.

To utilize the invention, an operator connects the UST line 4 c to thebottom 1 a of the canister 1. Then the inlet 5 is connected to the top 1b and the first branch control 6 and the second branch control 10 areconnected to the inlet 5. In operation, the canister communicates withthe UST. After a few refuelings, the pressure drops in the UST and inthe line 4 c and thus in the canister 1. The vacuum regulator 7 detectsthe pressure drop and opens to admit air from the intake 9 into canister1 and then into the line 4 c. The air passing through the carbon of thecanister strips any hydrocarbons therein and returns them to the UST.Once the pressure stabilizes in the UST, the vacuum regulator closes,stopping the inflow of air into the canister.

After additional refuelings, barometric pressure changes, and likeevents, the UST accumulates hydrocarbons under higher pressure. Thehigher pressure affects the canister of the vapor pressure managementsystem and the pressure regulator 11 opens at a certain pressure. Theopen second branch control 10 draws hydrocarbon laden air from the USTthrough the canister. The carbon in the canister strips the hydrocarbonsfrom the UST air and retains them upon the carbon. The cleansed air isthen released from the outlet 13. Once the pressure again stabilizes inthe UST, the pressure regulator closes the second branch control.

If the canister of the system clogs or otherwise fails and the USTpressure increases severely, the vent 4 has a pressure relief valve 4 athat opens. Opening of this valve is anticipated on the order of ahandful of hours per year. The cycle of purging and retaininghydrocarbons then repeats until the carbon is exhausted. The carbonexhausts after some years and requires replacement. The presentinvention permits ready replacement of the activated carbon, or otherform of carbon within the canister. In operation, the present inventionmaximizes the air introduced into the UST and minimizes any hydrocarbonsreleased from the UST.

FIG. 3 shows an alternate embodiment of the present invention intendedparticularly for use in a Stage II vapor recovery system with bothbranch controls communicating to the atmosphere through the same intake.As before, the canister 1 has a generally cylindrical shape, here shownupright, with a bottom 1 a and an opposite top 1 b. The bottom and thetop have openings to permit communication to the UST line 4 c and theinlet 5 respectively. The canister has a wall 1 c that connects with theperimeters of the top and the bottom to surround the canister. Thecanister contains activated charcoal and other carbon materials in dryform, generally filling the canister. Alternatively, the canistercontains activated charcoal suspended within an aqueous solution.

The inlet then proceeds to a tee 5 a that joins both branch controls.The first branch control, as at 6, communicates to the atmosphere fordrawing air through the intake 9 a, into the canister, and onwards tothe UST. The first branch control has a vacuum regulator 7 incommunication with a valve 8 that connects with a screened intake 9 a.The intake 9 a admits atmospheric air into the canister generally at alow pressure and when the vacuum regulator 7 opens.

From the tee 5 a in the opposite direction, the inlet 5 has a secondbranch control 10. The second branch control releases treated air fromthe canister to the atmosphere. The second branch control has a pressureregulator 11 in communication with the valve 8 that then connects withthe screened intake 9 a. The screened intake 9 a in the alternateembodiment both admits atmospheric air into the canister and releasescleansed air from the canister. Though the screened intake serves dualfunctions, the opposing functions of the vacuum regulator 7 and thepressure regulator 11 prevent recirculation of hydrocarbon vapors.

Similar to before, an operator connects the UST line 4 c to the bottom 1a of the canister 1 to operate the invention. Then the inlet 5 isconnected to the top 1 b and the first branch control 6 and the secondbranch control 10 are connected to the inlet 5 through the tee 5 a. Inoperation, the present invention communicates with the UST. After a fewrefuelings, the pressure drops in the UST and in the line 4 c and thusin the canister 1. The vacuum regulator 7 detects the pressure drop andopens to admit air from the intake 9 a, through the valve 8, and intocanister 1 and then into the line 4 c. The air passing through thecharcoal carbon of the canister strips any loose hydrocarbons thereinand returns them to the UST. Once the pressure stabilizes in the UST,the vacuum regulator closes, stopping the inflow of air into thecanister.

After additional refuelings, barometric pressure changes, and likeevents, the UST accumulates hydrocarbons under higher pressure. Thehigher pressure affects the canister of the vapor pressure managementsystem and the pressure regulator 11 opens at a certain pressure. Theopen second branch control 10 draws hydrocarbon laden air from the USTthrough the canister. The activated carbon in the canister strips thehydrocarbons from the UST air and retains them upon the activatedcarbon. The cleansed air is then returned from the canister through thepressure regulator out the intake 9 a and then to the atmosphere. Oncethe pressure again stabilizes in the UST, the pressure regulator closesthe second branch control.

If the canister of the system clogs or otherwise fails and the USTpressure increases severely, the vent 4 has a pressure relief valve 4 athat opens. Opening of this valve is anticipated on the order of ahandful of hours per year. The cycle of purging and retaininghydrocarbons then repeats until the charcoal carbon is exhausted. Theactivated carbon exhausts after some years and requires replacement. Thepresent invention permits ready replacement of the charcoal, activatedcarbon, or other carbon within the canister. In operation, the presentinvention maximizes the air introduced into the UST and minimizes anyhydrocarbons released from the UST.

FIG. 4 shows the arrangement of the present invention in communicationwith an UST. The UST has a stack 4 generally extending upwardly andterminating with an emergency pressure relief valve 4 a as describedabove. A line 4 c extends from the stack and communicates vapors to thecanister 1. The line 4 c has a shutoff valve 4 b outside of the canisterfor testing, repairs of the canister, or emergency shutoff of thesystem. The canister rests upon a stand 12 which generally elevates thecanister above the surface and permits access to piping components belowthe canister. The canister has a top 1 b generally located away from thesurface and an opposite bottom 1 a generally opposite the top. Beneaththe bottom, the canister has a second bottom 1 d generally inverted fromthe orientation of the bottom 1 a. A wall 1 c joins the top and thebottom forming a round cylindrical shape, preferably. Upon the top, aninlet 5 admits air into the canister when needed to purge hydrocarbonvapor from the carbon and return them to the UST. The inlet admits airgenerally upon pressure changes of the UST relative to ambientatmospheric pressure. Outwardly from the inlet, the top has two testports 27 generally equally spaced upon a diameter of the top. The testports have suitable threading or fittings to receive test equipment (notshown).

In a typical UST, a pressure vacuum valve, generally mechanical, ventsthe pressure and hydrocarbon emissions from a UST when the pressurereading exceeds 2.5 inches of water. However, some vapor processors,including the present invention, can release hydrocarbons when pressureexceeds a mere 0.25 inches of water. The order of magnitude reduction inpressure has concerned CARB because more hydrocarbons will be emitted byvapor processors intentionally or accidentally as vapor processors ageand wear. Additionally, such low pressure discharge levels will likelybypass the pressure vacuum valves, effectively neutralizing them.Further, CARB mandates that the pressure vacuum relief valve of the USTsystem takes control when a vapor processor fails. The present inventionprovides a mechanical closing of hydrocarbon communication into a nearlysaturated or saturated carbon canister and returns pressure control tothe pressure vacuum valve. The present invention allows the pressurevacuum relief valve 4 a to regulate hydrocarbon vapors that accumulatenear or at saturation of the canister at more than 2.5 inches of waterpressure.

Within the canister in this embodiment, FIG. 5 shows the valves andpiping that regulate the adsorption of hydrocarbon vapors by theinvention and the purging of hydrocarbon vapors with air admitted intothe invention. Within the canister 1, the present invention has agenerally cylindrical casing 13 c that holds carbon, activated carbon,charcoal or other hydrocarbon retaining substance as at 14. Theactivated carbon retains hydrocarbon vapors upon the surface of thecarbon pieces once introduced into the presence of the activated carbon.A rod 13 a extends axially through the carbon generally upon the axis ofthe casing. The rod contains the carbon and hydrocarbon vapors withinthe canister as the rod connects the top screen 23 and the bottom screen25 of the casing 13 c. Both screens include fine mesh and coarse mesh.The casing extends upwardly from the top screen to surround the union21. The casing seals to a diaphragm 13 d upon its upper limit proximatethe inlet 5. The diaphragm seal isolates the casing 13 c from the wall 1c of the canister. The diaphragm seal has a generally toroid, or donutlike, shape and extends around the perimeter of the casing and outwardlyto the inside of the canister wall 1 c.

When the activated carbon becomes saturated with hydrocarbons, airintroduced into the casing strips the hydrocarbon molecules from theactivated carbon for transmission back into the UST. The casing restsupon a weight sensitive valve assembly as at 15. The assembly has anupper plate 16 generally centered upon the bottom of the casing via rod13 a and an opposite base plate 17. The upper plate and the lower plateare aligned by at least two guide rods 18 generally parallel to thelength of the casing. These guide rods extend through the thicknesses ofboth plates and have nuts, or other means, preventing the plates fromslipping off the rods. Between the plates, the assembly has a biasingmeans, or spring 19, that maintains the plates spaced apart, at apredetermined distance, until the carbon within the casing attains acertain weight.

Generally centered upon the axis of the spring, a weight actuated valve20 remains open as in FIG. 5 until the carbon becomes saturated. Thevalve has a generally cylindrical shape, here shown in sectionconnecting to the top plate 16 and suspending above the seat 20 a aslater shown. The gap between the valve and the seat permits the flow ofhydrocarbon vapors from the line 4 c to enter the canister then passthrough the bottom screen 25 into the casing. Once the carbon inside thecasing becomes saturated or nearly saturated and its weight increases,the spring yields and the upper plate allows the bottom of the casing tomove valve 20 to descend upon the seat 20 a. The weight of the casingthen closes the valve against the seat as later shown in FIG. 6 andprevents hydrocarbon vapors from entering the casing. Adjacent to theweight actuated valve, the present invention includes a secondary purgevalve as at 28. The secondary purge valve receives hydrocarbon vaporsfrom air that has passed through the carbon 14 and the bottom screen 25.The secondary purge valve then releases hydrocarbon laden vapors throughthe valve 20 and into the line 4 c returning the hydrocarbons to theUST.

Above the casing, valves and piping regulate the flow of air andhydrocarbons into and through the casing and activated carbon as well asinto and through the UST. From the top in FIG. 5, the inlet extends to aunion 21 that in this embodiment has three stems, a first stem 21 acommunicates to the atmosphere outside of the canister. The second stem21 b, generally perpendicular to the first stem proceeds to a vacuumregulator 7 in communication with a purge valve 8 that connects with ascreened intake 9. The intake 9 admits atmospheric air into the canistergenerally at a low pressure and when the vacuum regulator 7 opens. Thesecond stem, cooperating with the purge valve, draws atmospheric airthrough the first stem and into the interior of the canister for purgingof hydrocarbon vapors from the saturated carbon and returning them tothe UST.

Opposite the second stem, a third stem 21 c, also perpendicular to thefirst stem, releases treated air from the canister to the atmosphere.The third stem has a pressure regulator 11 in communication with anoutlet valve 11 a, shown below the intake 9; however, other locationsare anticipated.

The present invention uses the loaded weight of the activated carbon 14within the casing 13 c to close the main check valve, as at 20, and torevert pressure control back to the P/V vent valve, as at 4 a. When theUST operates at a sufficient negative pressure, the secondary purgevalve 28 opens. The secondary purge valve then returns just enoughhydrocarbons to the UST that lightens the canister enough to open themain valve 20. As the main valve returns to an open state, as in FIGS.5, 5A, the present invention assumes pressure control from the P/V valveand then purges itself at a higher rate. This cycle then repeats at eachinstance when the carbon 14 within the casing 13 c becomes overloadedand overweight with hydrocarbons.

To utilize the present invention, particularly for Stage II vaporrecovery, an operator connects the UST line 4 c to the bottom 1 a of thecanister 1. Then the inlet 5 is opened to the atmosphere. In operation,the present invention operates in fluid communication with the UST. Thepresent invention operates in five modes: 1) normal loading, 2) shutoff,3) secondary purging, 4) normal purging, and 5) no flow.

Due to evaporating fuel, barometric pressure changes, and like events,the UST accumulates hydrocarbon vapors under higher pressure. The higherpressure affects the canister of the present invention and normalloading mode takes place when the UST pressure equals or exceeds 0.25inches of water. The pressure regulator 11 opens and draws hydrocarbonladen air from the UST into the line 4 c and up through the bottomscreen then through the activated carbon inside the casing 13 c. Theactivated carbon 14 filters all of the hydrocarbons from the influentvapors and allows clean air to exit from the inlet 5 as in the flowlines of FIG. 5 a. As the activated carbon adsorbs hydrocarbons, theweight of the casing, including the activated carbon, increases. Oncethe weight of the casing and activated carbon reaches a critical amount,the main valve 20 begins to close.

At shutoff, the main valve closes as in FIG. 6. The weight of the casingand activated carbon exceed the critical amount causing the spring 19 tocompress and close the valve 20. Upon closing the valve, the presentinvention interrupts fluid and vapor communication to the UST andpressure control returns to the P/V vent 4 a. As a safety and pollutioncontrol mechanism, the activated carbon requires minimum purging so thatthe present invention regains pressure control from the P/V vent.

As shown in FIG. 5B, the secondary purge valve 28 opens as the mainvalve remains closed from shutoff. The secondary purge valve admits justenough air to purge the carbon at a low rate, shown by the flow lines.Generally the secondary purge valve opens when the UST pressure reaches−1.75 inches of water or less. Once approximately ½ pound ofhydrocarbons have been purged and returned to the UST, the main valve 20opens and normal purging occurs.

During normal purging, incoming atmospheric air purges the activatedcarbon at a higher rate than in secondary purging, as shown by the flowlines in FIG. 5 c. After a few refuelings, the pressure drops in the USTand in the line 4 c and thus in the canister 1. The vacuum regulator 7detects the pressure drop and opens to admit air through the intake 9within the casing 13 c, out the bottom screen 25, and then into the line4 c. The air passing through the carbon of the canister strips anyhydrocarbons therein and returns them to the UST. The normal purgingreduces the overall weight of the casing by removing hydrocarbons fromwithin the activated carbon. In doing so, the normal purging keeps themain valve 20 open. Generally normal purging occurs and the main valveopens when the UST pressure reaches approximately −1.50 inches of wateror less.

Once the pressure stabilizes in the UST, the vacuum regulator closes,stopping the inflow of air into the canister. And no flow occurs withinthe present invention when the UST has a pressure between approximately+0.25 inches and approximately −1.5 inches of water. Within thispressure range, the present invention does not allow flow of air orhydrocarbon vapors into or out of the canister, even if the main valve20 is open. The present invention manages the UST pressure within anoptimal range to comply with CARB daily average pressure requirementsand to optimize vapor recovery performance at the fill neck interface.

However, some vapor processors, when the carbon is saturated, canrelease hydrocarbon emissions when pressure exceeds approximately +0.25inches of water. This low pressure release has concerned governmentalregulators due to higher hydrocarbon emissions either intentionally oraccidentally. Such low pressure discharge levels will likely bypass thepressure vacuum valves, effectively neutralizing them. Further, CARBmandates that the pressure vacuum valve of a vapor processor operatewhen a vapor processor fails. The present invention has a weightactuated valve 20 that prohibits hydrocarbon vapors from entering thecanister when the carbon is near or at saturation. The weight sensitivevalve in cooperation with the pressure regulator valve 11 controlshydrocarbon vapors admitted into the canister at pressures less thanapproximately 0.25 inches of water. Following purging of hydrocarbonvapors from the canister, the cleansed air from the canister is thenadmitted through the outlet valve 11 a, on into the union, and to theatmosphere through inlet 5. Once the pressure again stabilizes in theUST, the pressure regulator closes the outlet valve.

In more detail, FIG. 6 shows the casing 13 c of the carbon 14 and theweight actuated valve 20 beneath it. Inside of the canister wall 1 c,the casing has a generally cylindrical form. The bottom of the canisterhas a central aperture that admits the rod 13 a through the bottomscreen 25 and into the casing. Opposite the bottom of the canister, thecasing has a top screen 23 upon the carbon. The top screen 23 has acentral aperture so that it can slide upon the rod 13 a. The casingremains generally centered within the canister by a plurality of guideposts 22, generally located above the top screen and above the bottomscreen. A spring 24 locates coaxially upon the rod 13 a and upon the topscreen. The spring 24 extends from a support downwardly upon thethreaded rod and induces pressure upon the carbon that assists in theadsorption of hydrocarbon vapors. Opposite the top, the casing has around bottom screen 25 that serves as a floor for the carbon and thatadmits hydrocarbon vapors. The canister also has an aperture that admitsthe other end of the rod, as a stem 13 b. This stem 13 b rests freely ona beveled outer surface that engages the weight actuated valve 20. Whenthe carbon is near or at saturation, the casing compresses the spring 19and descends. In descending, the casing guides the stem 13 b to push thevalve 20 upon the seat 20 a. Following the stem contacting the valve andpushing it on the seat in a tight fit, normal transmission ofhydrocarbon vapors into the canister and the casing ceases.

The upper plate 16 has a centered and raised portion, as at 16 a,extending into and towards the interior of the casing. The centeredraised portion fits around and over the valve 20. Beneath the upperplate 16, the spring 19 is coaxial with the UST line entering thecanister. The spring is located within the valve 20, generally acylindrical wall as at 26 that prevents accumulation of debris and othercontamination upon the wraps of the spring. The spring has acoefficient, k, and a length that operate such that when the knownweight of carbon within the casing is near or at saturation withhydrocarbons and the apparent weight of the carbon increases, the springcompresses allowing the valve to close upon the seat. As before, thespring rests upon the base plate 17. The base plate and the upper platemaintain alignment using the guide rods 18 that guide movement of theupper plate vertically under the action of the spring 19. The weightactuated valve assembly rests upon the outlet fitting 4 c proximate thecanister which is joined at the base plate 17 to the bottom 1 a of thecanister which is then connected to the stand 12 for positioning on theUST line 4 c near a UST at a GDF.

FIG. 7 shows a top view of the canister 1 c with the casing 13 c spacedaway from the canister using a plurality of guideposts 22. Theguideposts are generally equally spaced around the perimeter of thecasing. Though six guideposts are shown, the invention can operate upona minimum of three guideposts equally spaced apart.

It has been found desirable to be able to test the operation of theweight activated valve employed for the Stage II forms of the inventionto ensure proper operation thereof. Accordingly, additional features andcomponents for performance of such testing, such as are depicted in FIG.8, may be employed with the canisters with weight activated valves. Withparticular reference to the alternative canister embodiment depicted inFIG. 8, the upper portion of the canister may be considered highlysimilar to or substantially like the upper portion of the canister ofFIG. 5, with a modified lower portion as depicted in FIG. 8.

FIG. 8 shows a canister skirt 30 at the bottom of canister 1, with thepiping 4 c for communication with the underground tank positionedgenerally below the weight activated valve 20. In such embodiment, theweight activated valve 20, or main check valve, has been modified toallow for a rod 32 so the valve can be manually closed from outside thecanister 1. The rod 32 is contained within a pipe nipple 33, a pipecross 34, and a seal coupling 35 to allow external access to the maincheck valve assembly 20. A hole in the end of the rod 32 is used toinsert a hanger 36. The hanger 36 has a plate 38 at the lower endthereof to hold test weights (not shown) that may be inserted upon suchhanger 36.

When a main check valve field test is completed, the hanger 36 and plate38 may be removed and a cap structure 40, already shown in place in FIG.8 abutting seal coupling 35, as at 42, with a bottom cap thereon, may beinstalled on the seal coupling 35 to protect the rod 32 from weather.

Daily functioning of the weight activated valve 20 (to see if it is openor closed at any given time) can be indirectly observed by way of asight glass 44 installed with a surrounding O-ring 45 along the side ofthe cap structure 40 through which one or more reference lines ormarkers on the rod 32 can be viewed. In one preferred construction, ifthe reference line is not observable through the sight glass 44, theweight activated valve 20 is open, and, if the reference line isobservable to be at a designated point, the weight activated valve 20 isthen closed.

It should be appreciated that the foregoing discussion has addressed insome detail several embodiments of one form of the invention that isconsidered to be particularly adapted for use in or with Stage II vaporrecovery environments and systems, including an embodiment that permitstesting of the weight activated valve of such form by a technician.However, as has been briefly addressed hereinabove, another form of theinvention, which may in some ways be considered to be a simplifiedversion of the form addressed hereinabove, can be readily utilized inStage I vapor recovery systems, such as at service stations withoutStage II vapor recovery.

Such service stations often use conventional fuel dispensing nozzlesconnected by hoses to dispense fuel only, without returning any vaporfrom the vehicle to the vapor space of the fuel storage tank.

Such Stage I form of the invention includes a canister, which, like theStage II form of the invention, contains carbon, and is connected to thevapor space of the fuel storage tank in such a fashion as to allow anyexcess vapors to be freely vented out through the carbon. The carbontraps all, or substantially all, of the hydrocarbons so that only airescapes to the atmosphere.

During fueling, no vapors are returned to the vapor space of the fuelstorage tank from the vehicles being fueled.

Such activity creates a negative pressure in the vapor space resultingin fresh air being freely drawn in through the carbon canister purgingany hydrocarbons that I may have contained.

If, at any time, the vapor space develops excess vapors, as the resultof evaporation of some of the fuel when the station is not in operationor barometric pressure drops, the excess vapors will freely vent outthrough the carbon canister. The hydrocarbons will be trapped in thecarbon and only air will be vented to the atmosphere.

The carbon canister will never become saturated with hydrocarbonsbecause of the fresh air being freely drawn in as a result of fuelingvehicles without returning vapors.

Such Stage I vapor recovery system prevents the escape of hydrocarbonvapors to the atmosphere by the use of a carbon canister that isrepeatedly purged by the action of the fueling vehicles. The system isallowed to breathe freely in and out through the carbon canister so thatthe system is never at a positive pressure that would cause vapors todischarge to the atmosphere through leaks in the system. The canister isequipped with a flow limiting valve (surge valve) that prevents highflow rates through the canister in case an improper fuel delivery ismade.

No other means is necessary to keep the carbon canister functioning toremove the hydrocarbons from the vapor.

The canister of such a Stage I form of the invention is similar in manyrespects to, and includes many of the same or similar components as, theStage II form of the canister depicted in FIGS. 3-7. In such regard, theupper portion of the canister of the Stage I form of the invention isessentially the same as what is shown in FIG. 5.

FIG. 9 shows a sectional view of a preferred form of canister such asmay be utilized in a Stage I vapor recovery system. The canister 1 ofsuch form is similar in many respects to the canister previouslydescribed hereinabove, with carbon 14 disposed in a containment betweenan upper screen 23 and a lower screen 25 within the canister, and withpiping to atmosphere at the top end of the canister 1, as at inlet 5,and to the underground tank at the bottom 1 c of the canister 1, as atUST piping 4 c. A surge valve 50 is shown connected to inlet 5 toatmosphere within the canister 1 and inline with the carbon containmentin the flow path between atmosphere and the UST. A spacer 52 spaces thelower screen 25 above the bottom 1 a of canister 1 and a diffuser 54 ispreferably installed inline with the UST piping 4 c below the rod 13 aand held in place thereat by a diffuser cap 56. The canister is freebreathing in the manner as previously explained hereinabove whenutilized in Stage I vapor recovery systems, and the surge valve preventshigh flow rates through the canister in case an improper fuel deliveryis made.

Several forms of carbon canisters for use in Stage II and Stage I vaporrecovery systems have now been described in considerable detail in theforegoing. Such forms include a Stage II form that includes within thecarbon canister a valve activated by weight of nearly saturated orsaturated carbon, which form is uniquely capable of containinghydrocarbon vapors, returning them to a UST, and operating at pressureswith the range of approximately +0.50 inches of water and less thanapproximately −2.00 inches of water, and a Stage I form that includes afree-breathing carbon canister with only a surge valve for flow ratecontrol. In their various forms, the canisters of the present inventionand their various components may be manufactured from many materialsincluding, but not limited to, polymers, high density polyethylene HDPE,polypropylene PP, polyethylene terephalate ethylene PETE, polyvinylchloride PVC, polystyrene PS, nylon, steel, charcoal, activatedcharcoal, activated carbon, ferrous and non-ferrous metals, theiralloys, and composites.

In light of all the foregoing, it should thus be apparent to thoseskilled in the art that there have been shown and described variousforms of carbon canisters for the capture and purging of hydrocarbonvapors as air is drawn into an underground storage tank and releasedtherefrom. However, it should also be apparent that, within theprinciples and scope of the invention, many changes are possible andcontemplated, including in the details, materials, and arrangements ofparts which have been described and illustrated to explain the nature ofthe invention. Thus, while the foregoing description and discussionaddresses certain preferred embodiments or elements of the invention, itshould further be understood that concepts of the invention, as basedupon the foregoing description and discussion, may be readilyincorporated into or employed in other embodiments and constructionswithout departing from the scope of the invention. Accordingly, thefollowing claims are intended to protect the invention broadly as wellas in the specific form shown, and all changes, modifications,variations, and other uses and applications which do not depart from thespirit and scope of the invention are deemed to be covered by theinvention, which is limited only by the claims which follow.

What is claimed is:
 1. A device for cleansing hydrocarbon vapors andother contaminants comprising: a casing containing a hydrocarbonadsorption substance therein, having a screened bottom and an oppositescreened top, said bottom receiving hydrocarbon vapors from ahydrocarbon source; a weight actuated valve locating beneath saidcasing, said valve closing when said casing attains a predeterminedweight including hydrocarbons; an assembly locating opposite said weightactuated valve and in fluid communication with said casing, saidassembly drawing air into said casing when the hydrocarbon source hasattained a low pressure of approximately −1.5 inches of water; asecondary purge valve locating proximate said weight actuated valve,said secondary purge valve opening upon detecting pressure in thehydrocarbon source below approximately −1.75 inches of water when saidweight actuated valve has closed, then said secondary purge valveadmitting air into said casing, said secondary purge valve returningpurged hydrocarbon vapors from said hydrocarbon adsorption substancethrough said weight actuated valve into said hydrocarbon source, andsaid weight actuated valve reopening upon said casing falling below thepredetermined weight; and, a canister containing said casing, saidweight actuated valve, and said assembly, said canister being in fluidcommunication with said hydrocarbon source and allowing said assemblyfluid communication to the atmosphere; wherein the inflow of air throughsaid canister into said casing purges the hydrocarbon adsorptionsubstance of hydrocarbons and the outflow of air from said casingthrough said canister draws vapors from the hydrocarbon source throughsaid casing for adsorption by the hydrocarbon adsorption substance;wherein said weight actuated valve signals said assembly to controlrelease of hydrocarbon vapors and intake of air using pressure; and,wherein the repetitive inflow of air through said casing regenerates thehydrocarbon adsorption substance; and further including a valve testassembly for testing operation of the weight actuated valve, including aweight hanger extending below said canister and operatively connected tosaid weight actuated valve to effect closing thereof when sufficientweight is added to said weight hanger; wherein a user can add weights tosaid hanger to manually verify operability of said weight actuatedvalve.
 2. The hydrocarbon vapor cleansing device of claim 1 furthercomprising: said canister having an inlet in communication with saidassembly and an opposite outlet in communication with said weightactuated valve; said assembly having a union having three stems inmutual communication, a first stem in communication with said inlet, asecond stem in communication with said first stem and having a vacuumregulator in communication with a purge valve, said vacuum regulatoropening to admit air into said casing upon detecting a low pressure ofapproximately −1.5 inches of water within the hydrocarbon source, and athird stem in communication with said first stem and having a pressureregulator in communication with an outlet valve, said pressure regulatoropening to release air cleansed of hydrocarbon vapors when a highpressure within said casing is detected; wherein said assembly preventsflow through the inlet for pressures in the hydrocarbon source in therange of approximately +0.25 inches of water to approximately −1.50inches of water.
 3. The hydrocarbon vapor cleansing device of claim 1further comprising: a line connecting to said canister then to a valvewhich communicates to a vent stack, said vent stack in communicationwith the hydrocarbon source and including a pressure vacuum relief valveabove said line.
 4. The hydrocarbon vapor cleansing device of claim 1further comprising: a rod, generally centered within said casing andextending lengthwise through said casing, said rod connecting to saidscreened bottom; said screened top admitting said rod and securing tosaid canister upon its perimeter, said rod having a biasing mechanismsupplying a downward force upon said screened top and pressure upon saidhydrocarbon adsorption substance within said casing; and, said weightactuated valve having a base plate upon said bottom of said canister andupon said outlet to said canister, a spring upon said base plate, anupper plate opposite said base plate and above said spring, and at leastone guides parallel to the length of said casing, upon which said baseplate and said upper plate slidingly engage.
 5. The hydrocarbon removingdevice of claim 4 wherein said rod extends to below said canister andsaid weight hanger is removably attachable to said rod; and wherein saidvalve test assembly further includes piping into which said rod extends;said piping includes a sight glass along its length for observing aportion of said rod therethrough; and said rod includes one or moremarkings along said portion thereof observable through said sight glassindicative of a given state of said weight activated valve.
 6. Thehydrocarbon removing device of claim 1 wherein said hydrocarbonadsorption substance is selected from one of carbon, activated carbon,charcoal, or activated charcoal.
 7. A device to remove hydrocarbonvapors from air discharged from a hydrocarbon source under ambientatmospheric pressure conditions while retaining control by a pressurerelief valve during lower ambient pressure, comprising: a casingcontaining a substance adapted to remove hydrocarbon vapors from airwherein the inflow of air into said casing purges said substance ofhydrocarbons and the outflow of air from said casing draws vapors fromthe hydrocarbon source through said casing for adsorption by saidsubstance, wherein the repetitive inflow of air through said casingregenerates said substance; said casing having a screened bottom and anopposite screened top, and a rod extending through the centers of saidscreened bottom and said screened top; a weight actuated valve locatingbeneath said casing, said valve closing when said casing attains apredetermined weight of said substance including adsorbed hydrocarbons;an assembly locating within said casing and opposite said weightactuated valve locating outside said casing and in fluid communicationwith said casing, said assembly drawing air into said casing when saidweight actuated valve has opened and the hydrocarbon source has attaineda low pressure or when said weight actuated valve has closed and saidcasing has attained a lower pressure than atmospheric pressure; asecondary purge valve locating proximate said weight actuated valve,said secondary purge valve opening upon detecting pressure in thehydrocarbon source below approximately −1.75 inches of water thenadmitting air when said weight actuated valve is closed, and directingpurged hydrocarbon vapors through said weight actuated valve into saidhydrocarbon source wherein said weight actuated valve reopens upon saidcasing falling below the predetermined weight; and, a canistercontaining said casing, said weight actuated valve, and said secondarypurge valve, said canister being in fluid communication with saidhydrocarbon source and allowing said assembly fluid communication to theatmosphere, and said casing having a diaphragm seal to said canisteropposite said hydrocarbon source; wherein said assembly prevents flowthrough the inlet for pressures in the hydrocarbon source in the rangeof approximately +0.25 inches of water to approximately −1.5 inches ofwater; and further including a valve test assembly for testing operationof the weight actuated valve, including a weight hanger extending belowsaid canister and operatively connected to said weight actuated valve toeffect closing thereof when sufficient weight is added to said weighthanger; wherein a user can add weights to said hanger to manually verifyoperability of said weight actuated valve.
 8. The hydrocarbon removingdevice of claim 7 further comprising: said canister having an inlet incommunication with said assembly and an outlet in communication withsaid weight actuated valve; said assembly having a union including threestems in mutual communication, a first stem in communication with saidinlet, a second stem in communication with said first stem and having avacuum regulator in communication with a purge valve, said vacuumregulator opening to admit air into said casing upon detecting a lowpressure of approximately −1.5 inches of water within the hydrocarbonsource, and, a third stem in communication with said first stem andhaving a pressure regulator in communication with an outlet valve, saidpressure regulator opening to release air cleansed of hydrocarbon vaporsupon detecting a lower pressure within said casing.
 9. The hydrocarbonremoving device of claim 7 further comprising: a line communicating tosaid canister and then communicating to a vent stack, said vent stackcommunicating with the hydrocarbon source and including a pressurevacuum relief valve above said line.
 10. The hydrocarbon removing deviceof claim 7 wherein said substance is selected from one of carbon,activated carbon, charcoal, or activated charcoal.
 11. The hydrocarbonremoving device of claim 8 further comprising: said device processingvapors from the hydrocarbon source during normal loading at a pressurein the hydrocarbon source at least +0.25 inches of water; said assemblyshutting off flow through said device upon closure of said weightactuated valve by said canister achieving a predetermined weight; saiddevice performing secondary purging of said canister using saidsecondary purge valve at a pressure in the hydrocarbon source of atleast −1.75 inches of water upon said weight actuated valve remainingclosed; said device then performing normal purging at a pressure in thehydrocarbon source of at least −1.50 inches of water when said weightactuated valve is open; and, said device operating in a no flow state ata pressure in the hydrocarbon source in the range of approximately +0.25inches of water to −1.5 inches of water.
 12. A device for cleansinghydrocarbon vapors and other contaminants comprising: a canisterincluding a hydrocarbon adsorption substance disposed therein between ascreened bottom and an opposite screened top, said contained hydrocarbonadsorption substance defining a containment, with said bottom in fluidcommunication with a hydrocarbon source and receiving hydrocarbon vaporsfrom a hydrocarbon source and said top in fluid communication withatmosphere; a surge valve disposed inline with said containment in theflow path between atmosphere and the hydrocarbon source for limitingflow through said containment and preventing high flow rates throughsaid containment; wherein the inflow of air through said canister intosaid containment purges the hydrocarbon adsorption substance ofhydrocarbons and the outflow of air from said containment through saidcanister draws vapors from the hydrocarbon source through saidcontainment for adsorption by said hydrocarbon adsorption substance;and, wherein the repetitive inflow of air through said containmentregenerates said hydrocarbon adsorption substance.
 13. The hydrocarbonvapor cleansing device of claim 12 further comprising: a line connectingto said canister then to a valve which communicates to a vent stack,said vent stack in communication with the hydrocarbon source andincluding a pressure vacuum relief valve above said line.
 14. Thehydrocarbon vapor cleansing device of claim 12 wherein said surge valveis disposed above said containment within said canister in the path offluid communication with atmosphere.
 15. The hydrocarbon removing deviceof claim 12 wherein said substance is selected from one of carbon,activated carbon, charcoal, or activated charcoal.
 16. A device toremove hydrocarbon vapors from air discharged from a hydrocarbon sourceunder ambient atmospheric pressure conditions while retaining control bya pressure relief valve during lower ambient pressure, comprising: acanister; a containment within said canister containing a substanceadapted to remove hydrocarbon vapors from air wherein the inflow of airinto said casing purges said substance of hydrocarbons and the outflowof air from said casing draws vapors from the hydrocarbon source throughsaid casing for adsorption by said substance, wherein the repetitiveinflow of air through said casing regenerates said substance, saidcontainment having a screened bottom and an opposite screened top; asurge valve locating proximate said containment and inline with saidcontainment in the flow path between atmosphere and the hydrocarbonsource for limiting flow through said containment and preventing highflow rates through said containment.
 17. The hydrocarbon removing deviceof claim 16 wherein said surge valve is disposed above said containmentwithin said canister in the path of fluid communication with atmosphere.18. The hydrocarbon removing device of claim 16 further comprising: aline communicating to said canister and then communicating to a ventstack, said vent stack communicating with the hydrocarbon source andincluding a pressure vacuum relief valve above said line.
 19. Thehydrocarbon removing device of claim 16 wherein said substance isselected from one of carbon, activated carbon, charcoal, or activatedcharcoal.